A high-pressure pump, for example of the type described in our U.S. Pat. No. 4,218,961 to which reference should be made for further details, has a pump housing in which a piston is reciprocated. This piston normally projects from one end of the pump housing into a valve-assembly housing which has a main central bore aligned with the bore or cylinder of the pump housing and a transverse bore crossing this central bore and subdivided thereby into an intake-bore part and an exhaust-bore part. Respective intake and exhaust ports and intake and exhaust valves are provided in these bore parts so that with each reciprocation of the piston the pump fluid will be drawn in through the intake port and valve and then exhausted through the exhaust valve and port. Such a valve assembly can be seen in our copending application Ser. No. 948,542 (now U.S. Pat. No. 3,256,139).
The main problem with such arrangements is that the valve housing fails after a relatively short service life. This valve housing is subjected to very high operating pressure and frequently also to pressure peaks that are sufficiently large to crack the housing. The high-pressure fluid erodes the bores relatively rapidly and can, in fact, cause virtually explosive failure of the valve housing.
It is standard practice to make the valve housing of the most rugged possible materials, normally expensive and difficult-to-machine steel alloys.